The present invention relates generally to security devices for hand-operated wheeled vehicles, such as shopping carts, to deter theft of such vehicles, and is particularly concerned with a braking shell forming part of such a security device which is arranged to be deployed on actuation to rotate down into contact with the ground in order to inhibit wheel rotation.
In U.S. Pat. Nos. 5,881,846 and 6,125,972 of French et al., a shopping cart security apparatus and system is described in which a braking member in the form of a shell is rotatably mounted on the wheel axle of one of the wheels, so as to partially surround the wheel. The shell is movable between a raised, inoperative position in which it does not contact the ground, and a lowered, operative position contacting the ground between the wheel and the ground, preventing rotation of the wheel. One problem with this arrangement is that the portion which contacts the ground, which is generally a skid plate, becomes worn over time and eventually needs to be replaced. This requires the entire caster to be removed from the cart so that the shell can be removed from the wheel axle and replaced or repaired. This makes the cost and time required for maintenance relatively high.